Tire control system

The Problem:

The Firestone recall from the late 1990s, linked to more than 100 deaths in the US following tire separation, lead to the TREAD Act, which mandated the use of a suitable tire pressure monitoring system (TPMS) technology in all light motor vehicles. In the US the act affects all vehicles sold after September 1, 2007.

As of November 1, 2012, all new passenger car models (M1) released in the European Union must be equipped with a TPMS. From November 1, 2014, all new passenger cars sold in the European Union must be equipped with TPMS.

The Solution:

Our customer produces and distributes TPMS technology at a large scale and faces a shortage of qualified specialists to develop the software component. It also patented a software solution that can identify and record (learn) the ID of the car's tires using information directly from the ABS sensor. The tires are fitted with inexpensive and robust sensors, which replace the expensive antennas that had been previously used. These antennas were not only costly but also prone to destruction at any repair that required tire removal.

Diagnosis gives the vehicle owner or a repair technician access to state of health information for various vehicle sub-systems. Through diagnosis Data Trouble Code (DTC) errors are detected, validated and recorded in the Electronic Control Unit (ECU) memory. The AROBS team managed around 30 such errors, such as under-voltage and over-voltage for the entire car system, ECU internal failures, invalid wheel (this can suggest a sensor malfunction, among others), communication protocol (CAN) errors, etc. The moment at which an error is identified is recorded, both as mileage spent and as date and time, up to seconds.

When a car owner visits the car service station for a check, the mechanic runs some tests using diagnosis services like read/write, which use the previously recorded DTC information, routines, and other services to read various data, such as the vehicle identification number. Some of this data is provided by the diagnosis services implemented by the AROBS specialists, which include, among others, reading information on errors saved at the diagnosis stage and reading data about the car (e.g. car ID, the version of the software installed in the car, the car calibration parameters, etc).

Challenges:

Integrating third party components in an already high complexity system was the main hurdle of the project, since each of these components has unique communication and functional characteristics. Intensive research, through hundreds of pages of dense technical documentation, helped our engineers overcome the difficulties. As each word of the documentation could provide key answers, attention to even the tiniest detail proved crucial. Around 95% of all the integration related issues were solved by the AROBS engineers, without any support from the customer.

The second challenge was to optimize the system from the very beginning, to the extent that only minor lab and on the road testing were required to convert the alpha version of the solution into the final, defect-free product. To achieve this goal we made sure the memory did not get fragmented and written more or more often than necessary. Based on historic data, errors have been grouped according to the frequency with which they occur and different groups were allocated different parts of the memory. This optimized the memory usage and the speed of the entire system.

Results:

Lab system, integration, and live testing have been performed with excellent results. The system is reliable, providing all the programmed notifications on the car's display (e.g. wheels are functional, low wheel pressure, missing wheel, etc.).